/** BEGIN COPYRIGHT BLOCK
 * Copyright 2004 Netscape Communications Corporation
 * All rights reserved.
 * END COPYRIGHT BLOCK **/

#include "acl.h"

static int
_ger_g_permission_granted ( Slapi_PBlock *pb, Slapi_Entry *e, char **errbuf )
{
	char *proxydn = NULL;
	Slapi_DN *requestor_sdn, *entry_sdn;
	char *errtext = NULL;
	int isroot;
	int rc;

	/*
	 * Theorically, we should check if the entry has "g"
	 * permission granted to the requestor. If granted,
	 * allows the effective rights on that entry and its
	 * attributes within the entry to be returned for
	 * ANY subject.
	 *
	 * "G" permission granting has not been implemented yet,
	 * the current release assumes that "g" permission be 
	 * granted to root and owner of any entry.
	 */

	/*
	 * The requestor may be either the bind dn or a proxy dn
	 */
	acl_get_proxyauth_dn ( pb, &proxydn, &errtext );
	if ( proxydn != NULL )
	{
		requestor_sdn = slapi_sdn_new_dn_passin ( proxydn );
	}
	else
	{
		requestor_sdn = &(pb->pb_op->o_sdn);
	}
	if ( slapi_sdn_get_dn (requestor_sdn) == NULL )
	{
		slapi_log_error (SLAPI_LOG_ACL, plugin_name,
				"_ger_g_permission_granted: anonymous has no g permission\n" );
		rc = LDAP_INSUFFICIENT_ACCESS;
		goto bailout;
	}
	isroot = slapi_dn_isroot ( slapi_sdn_get_dn (requestor_sdn) );
	if ( isroot )
	{
		/* Root has "g" permission on any entry */
		rc = LDAP_SUCCESS;
		goto bailout;
	}

	entry_sdn = slapi_entry_get_sdn ( e );
	if ( entry_sdn == NULL || slapi_sdn_get_dn (entry_sdn) == NULL )
	{
		rc = LDAP_SUCCESS;
		goto bailout;
	}

	if ( slapi_sdn_compare ( requestor_sdn, entry_sdn ) == 0 )
	{
		/* Owner has "g" permission on his own entry */
		rc = LDAP_SUCCESS;
		goto bailout;
	}

	aclutil_str_appened ( errbuf, "get-effective-rights: requestor has no g permission on the entry" );
	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
				"_ger_g_permission_granted: %s\n", *errbuf);
	rc = LDAP_INSUFFICIENT_ACCESS;

bailout:
	if ( proxydn )
	{
		/* The ownership of proxydn has passed to requestor_sdn */ 
		slapi_sdn_free ( &requestor_sdn );
	}
	return rc;
}

static int
_ger_parse_control ( Slapi_PBlock *pb, char **subjectndn, int *iscritical, char **errbuf )
{
	LDAPControl **requestcontrols;
	struct berval *subjectber;
	BerElement *ber;

	if (NULL == subjectndn)
	{
		return LDAP_OPERATIONS_ERROR;
	}

	*subjectndn = NULL;

	/*
	 * Get the control
	 */
	slapi_pblock_get ( pb, SLAPI_REQCONTROLS, (void *) &requestcontrols );
	slapi_control_present ( requestcontrols,
							LDAP_CONTROL_GET_EFFECTIVE_RIGHTS,
							&subjectber,
							iscritical );
	if ( subjectber == NULL || subjectber->bv_val == NULL ||
		 subjectber->bv_len == 0 )
	{
		aclutil_str_appened ( errbuf, "get-effective-rights: missing subject" );
		slapi_log_error (SLAPI_LOG_FATAL, plugin_name, "%s\n", *errbuf );
		return LDAP_INVALID_SYNTAX;
	}

	if ( strncasecmp ( "dn:", subjectber->bv_val, 3 ) == 0 )
	{
		/*
		 * This is a non-standard support to allow the subject being a plain
		 * or base64 encoding string. Hence users using -J option in
		 * ldapsearch don't have to do BER encoding for the subject.
		 */
		*subjectndn = slapi_ch_malloc ( subjectber->bv_len + 1 );
		strncpy ( *subjectndn, subjectber->bv_val, subjectber->bv_len );
		*(*subjectndn + subjectber->bv_len) = '\0';
	}
	else
	{
		ber = ber_init (subjectber);
		if ( ber == NULL )
		{
			aclutil_str_appened ( errbuf, "get-effective-rights: ber_init failed for the subject" );
			slapi_log_error (SLAPI_LOG_FATAL, plugin_name, "%s\n", *errbuf );
			return LDAP_OPERATIONS_ERROR;
		}
		/* "a" means to allocate storage as needed for octet string */
		if ( ber_scanf (ber, "a", subjectndn) == LBER_ERROR )
		{
			aclutil_str_appened ( errbuf, "get-effective-rights: invalid ber tag in the subject" );
			slapi_log_error (SLAPI_LOG_FATAL, plugin_name, "%s\n", *errbuf );
			ber_free ( ber, 1 );
			return LDAP_INVALID_SYNTAX;
		}
		ber_free ( ber, 1 );
	}

	/*
	 * The current implementation limits the subject to authorization ID
	 * (see section 9 of RFC 2829) only. It also only supports the "dnAuthzId"
	 * flavor, which looks like "dn:<DN>" where null <DN> is for anonymous.
	 */
	if ( NULL == *subjectndn || strlen (*subjectndn) < 3 ||
		 strncasecmp ( "dn:", *subjectndn, 3 ) != 0 )
	{
		aclutil_str_appened ( errbuf, "get-effective-rights: subject is not dnAuthzId" );
		slapi_log_error (SLAPI_LOG_FATAL, plugin_name, "%s\n", *errbuf );
		return LDAP_INVALID_SYNTAX;
	}

	strcpy ( *subjectndn, *subjectndn + 3 );
	slapi_dn_normalize ( *subjectndn );
	return LDAP_SUCCESS;
}

static void
_ger_release_gerpb (
	Slapi_PBlock **gerpb,
	void		 **aclcb,	/* original aclcb */
	Slapi_PBlock *pb		/* original pb */
	)
{
	if ( *gerpb )
	{
		/* Return conn to pb */
		slapi_pblock_set ( *gerpb, SLAPI_CONNECTION, NULL );
		slapi_pblock_destroy ( *gerpb );
		*gerpb = NULL;
	}

	/* Put the original aclcb back to pb */
	if ( *aclcb )
	{
		Connection *conn = NULL;
		slapi_pblock_get ( pb, SLAPI_CONNECTION, &conn );
		if (conn)
		{
			struct aclcb *geraclcb;
			geraclcb = (struct aclcb *) acl_get_ext ( ACL_EXT_CONNECTION, conn );
			acl_conn_ext_destructor ( geraclcb, NULL, NULL );
			acl_set_ext ( ACL_EXT_CONNECTION, conn, *aclcb );
			*aclcb = NULL;
		}
	}
}

static int
_ger_new_gerpb (
	Slapi_PBlock    *pb,
	Slapi_Entry	    *e,
	const char 		*subjectndn,
	Slapi_PBlock	**gerpb,
	void			**aclcb,	/* original aclcb */
	char			**errbuf
	)
{
	Connection *conn;
	struct acl_cblock *geraclcb;
	Acl_PBlock *aclpb, *geraclpb;
	Operation *op, *gerop;
	int rc = LDAP_SUCCESS;

	*aclcb = NULL;
	*gerpb = slapi_pblock_new ();
	if ( *gerpb == NULL )
	{
		rc = LDAP_NO_MEMORY;
		goto bailout;
	}

	{
		/* aclpb initialization needs the backend */
		Slapi_Backend *be;
		slapi_pblock_get ( pb, SLAPI_BACKEND, &be );
		slapi_pblock_set ( *gerpb, SLAPI_BACKEND, be );
	}

	{
		int isroot = slapi_dn_isroot ( subjectndn );
		slapi_pblock_set ( *gerpb, SLAPI_REQUESTOR_ISROOT, &isroot );
	}

	/* Save requestor's aclcb and set subjectdn's one */
	{
		slapi_pblock_get ( pb, SLAPI_CONNECTION, &conn );
		slapi_pblock_set ( *gerpb, SLAPI_CONNECTION, conn );

		/* Can't share the conn->aclcb because of different context */
		geraclcb = (struct acl_cblock *) acl_conn_ext_constructor ( NULL, NULL);
		if ( geraclcb == NULL )
		{
			rc = LDAP_NO_MEMORY;
			goto bailout;
		}
		slapi_sdn_set_ndn_byval ( geraclcb->aclcb_sdn, subjectndn );
		*aclcb = acl_get_ext ( ACL_EXT_CONNECTION, conn );
		acl_set_ext ( ACL_EXT_CONNECTION, conn, (void *) geraclcb );
	}

	{
		gerop = operation_new ( OP_FLAG_INTERNAL );
		if ( gerop == NULL )
		{
			rc = LDAP_NO_MEMORY;
			goto bailout;
		}
		/*
		 * conn is a no-use parameter in the functions
		 * chained down from factory_create_extension
		 */
		gerop->o_extension = factory_create_extension ( get_operation_object_type(), (void *)gerop, (void *)conn );
		slapi_pblock_set ( *gerpb, SLAPI_OPERATION, gerop );
		slapi_sdn_set_dn_byval ( &gerop->o_sdn, subjectndn );
		geraclpb = acl_get_ext ( ACL_EXT_OPERATION, (void *)gerop);
		acl_init_aclpb ( *gerpb, geraclpb, subjectndn, 0 );
		geraclpb->aclpb_res_type |= ACLPB_EFFECTIVE_RIGHTS;
	}


bailout:
	if ( rc != LDAP_SUCCESS )
	{
		_ger_release_gerpb ( gerpb, aclcb, pb );
	}

	return rc;
}

/*
 * Callers should have already allocated *gerstr to hold at least
 * "entryLevelRights: adnvxxx\n".
 */
unsigned long
_ger_get_entry_rights (
	Slapi_PBlock *gerpb,
	Slapi_Entry *e,
	const char *subjectndn,
	char *gerstr,
	char **errbuf
	)
{
	unsigned long entryrights = 0;
	Slapi_RDN *rdn = NULL;
	const char *rdnstr = NULL;
	char *equalsign = NULL;
	char *rdntype = NULL;

	strcpy ( gerstr, "entryLevelRights: " );

	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
		"_ger_get_entry_rights: SLAPI_ACL_READ\n" );
	if (acl_access_allowed(gerpb, e, "*", NULL, SLAPI_ACL_READ) == LDAP_SUCCESS)
	{
		/* v - view e */
		entryrights |= SLAPI_ACL_READ;
		strcat (gerstr, "v");
	}
	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
		"_ger_get_entry_rights: SLAPI_ACL_ADD\n" );
	if (acl_access_allowed(gerpb, e, NULL, NULL, SLAPI_ACL_ADD) == LDAP_SUCCESS)
	{
		/* a - add child entry below e */
		entryrights |= SLAPI_ACL_ADD;
		strcat (gerstr, "a");
	}
	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
		"_ger_get_entry_rights: SLAPI_ACL_DELETE\n" );
	if (acl_access_allowed(gerpb, e, NULL, NULL, SLAPI_ACL_DELETE) == LDAP_SUCCESS)
	{
		/* d - delete e */
		entryrights |= SLAPI_ACL_DELETE;
		strcat (gerstr, "d");
	}
	/*
	 * Some limitation/simplification applied here:
	 * - The modrdn right requires the rights to delete the old rdn and
	 *   the new one. However we have no knowledge of what the new rdn
	 *   is going to be.
	 * - In multi-valued RDN case, we check the right on
	 *   the first rdn type only for now.
	 */
	rdn = slapi_rdn_new_dn ( slapi_entry_get_ndn (e) );
	rdnstr = slapi_rdn_get_rdn ( rdn );
	if ( NULL != (equalsign = strchr ( rdnstr, '=' )) )
	{
		rdntype = slapi_ch_malloc ( equalsign-rdnstr+1 );
		strncpy ( rdntype, rdnstr, equalsign-rdnstr );
		rdntype [ equalsign-rdnstr ] = '\0';
		slapi_log_error (SLAPI_LOG_ACL, plugin_name,
			"_ger_get_entry_rights: SLAPI_ACL_WRITE_DEL & _ADD %s\n", rdntype );
		if (acl_access_allowed(gerpb, e, rdntype, NULL,
				ACLPB_SLAPI_ACL_WRITE_DEL) == LDAP_SUCCESS &&
			acl_access_allowed(gerpb, e, rdntype, NULL,
				ACLPB_SLAPI_ACL_WRITE_ADD) == LDAP_SUCCESS)
		{
			/* n - rename e */
			entryrights |= SLAPI_ACL_WRITE;
			strcat (gerstr, "n");
		}
		slapi_ch_free ( (void**) &rdntype );
	}
	slapi_rdn_free ( &rdn );

done:
	if ( entryrights == 0 )
	{
		strcat (gerstr, "none");
	}

	strcat (gerstr, "\n");

	return entryrights;
}

/*
 * *gerstr should point to a heap buffer since it may need
 * to expand dynamically.
 */
unsigned long
_ger_get_attr_rights (
	Slapi_PBlock *gerpb,
	Slapi_Entry *e,
	const char *subjectndn,
	char *type,
	char **gerstr,
	int *gerstrsize,
	int isfirstattr,
	char **errbuf
	)
{
	unsigned long attrrights = 0;

	/* Enough space for " $type:rwoscxx" ? */
	if ( (*gerstrsize - strlen(*gerstr)) < (strlen(type) + 16) )
	{
		/* slapi_ch_realloc() exits if realloc() failed */
		*gerstrsize += 256;
		*gerstr = slapi_ch_realloc ( *gerstr, *gerstrsize );
	}
	if (!isfirstattr)
	{
		strcat ( *gerstr, ", " );
	}
	sprintf ( *gerstr + strlen(*gerstr), "%s:", type );

	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
		"_ger_get_attr_rights: SLAPI_ACL_READ %s\n", type );
	if (acl_access_allowed(gerpb, e, type, NULL, SLAPI_ACL_READ) == LDAP_SUCCESS)
	{
		/* r - read the values of type */
		attrrights |= SLAPI_ACL_READ;
		strcat (*gerstr, "r");
	}
	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
		"_ger_get_attr_rights: SLAPI_ACL_SEARCH %s\n", type );
	if (acl_access_allowed(gerpb, e, type, NULL, SLAPI_ACL_SEARCH) == LDAP_SUCCESS)
	{
		/* s - search the values of type */
		attrrights |= SLAPI_ACL_SEARCH;
		strcat (*gerstr, "s");
	}
	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
		"_ger_get_attr_rights: SLAPI_ACL_COMPARE %s\n", type );
	if (acl_access_allowed(gerpb, e, type, NULL, SLAPI_ACL_COMPARE) == LDAP_SUCCESS)
	{
		/* c - compare the values of type */
		attrrights |= SLAPI_ACL_COMPARE;
		strcat (*gerstr, "c");
	}
	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
		"_ger_get_attr_rights: SLAPI_ACL_WRITE_ADD %s\n", type );
	if (acl_access_allowed(gerpb, e, type, NULL, ACLPB_SLAPI_ACL_WRITE_ADD) == LDAP_SUCCESS)
	{
		/* w - add the values of type */
		attrrights |= ACLPB_SLAPI_ACL_WRITE_ADD;
		strcat (*gerstr, "w");
	}
	slapi_log_error (SLAPI_LOG_ACL, plugin_name,
		"_ger_get_attr_rights: SLAPI_ACL_WRITE_DEL %s\n", type );
	if (acl_access_allowed(gerpb, e, type, NULL, ACLPB_SLAPI_ACL_WRITE_DEL) == LDAP_SUCCESS)
	{
		/* o - delete the values of type */
		attrrights |= ACLPB_SLAPI_ACL_WRITE_DEL;
		strcat (*gerstr, "o");
	}
	/* If subjectdn has no general write right, check for self write */
	if ( 0 == (attrrights & (ACLPB_SLAPI_ACL_WRITE_DEL | ACLPB_SLAPI_ACL_WRITE_ADD)) )
	{
		struct berval val;

		val.bv_val = (char *)subjectndn;
		val.bv_len = strlen (subjectndn);

		if (acl_access_allowed(gerpb, e, type, &val, ACLPB_SLAPI_ACL_WRITE_ADD) == LDAP_SUCCESS)
		{
			/* W - add self to the attribute */
			attrrights |= ACLPB_SLAPI_ACL_WRITE_ADD;
			strcat (*gerstr, "W");
		}
		if (acl_access_allowed(gerpb, e, type, &val, ACLPB_SLAPI_ACL_WRITE_DEL) == LDAP_SUCCESS)
		{
			/* O - delete self from the attribute */
			attrrights |= ACLPB_SLAPI_ACL_WRITE_DEL;
			strcat (*gerstr, "O");
		}
	}

	if ( attrrights == 0 )
	{
		strcat (*gerstr, "none");
	}

	return attrrights;
}

void
_ger_get_attrs_rights (
	Slapi_PBlock *gerpb,
	Slapi_Entry *e,
	const char *subjectndn,
	char **attrs,
	char **gerstr,
	int *gerstrsize,
	char **errbuf
	)
{
	int isfirstattr = 1;

	/* gerstr was initially allocated with enough space for one more line */
	strcat ( *gerstr, "attributeLevelRights: " );

	if (attrs && *attrs)
	{
		int i;
		for ( i = 0; attrs[i]; i++ )
		{
			_ger_get_attr_rights ( gerpb, e, subjectndn, attrs[i], gerstr, gerstrsize, isfirstattr, errbuf );
			isfirstattr = 0;
		}
	}
	else
	{
		Slapi_Attr *prevattr = NULL, *attr;
		char *type;

		while ( slapi_entry_next_attr ( e, prevattr, &attr ) == 0 )
		{
			if ( ! slapi_attr_flag_is_set (attr, SLAPI_ATTR_FLAG_OPATTR) )
			{
				slapi_attr_get_type ( attr, &type );
				_ger_get_attr_rights ( gerpb, e, subjectndn, type, gerstr, gerstrsize, isfirstattr, errbuf );
				isfirstattr = 0;
			}
			prevattr = attr;
		}
	}

	if ( isfirstattr )
	{
		/* not a single attribute was retrived or specified */
		strcat ( *gerstr, "*:none" );
	}
	return;
}

/*
 * controlType = LDAP_CONTROL_GET_EFFECTIVE_RIGHTS;
 * criticality = n/a;
 * controlValue = OCTET STRING of BER encoding of the SEQUENCE of
 *				  ENUMERATED LDAP code
 */
void
_ger_set_response_control (
	Slapi_PBlock	*pb,
	int				iscritical,
	int				rc
	)
{
	LDAPControl **resultctrls = NULL;
	LDAPControl gerrespctrl;
	BerElement *ber = NULL;
	struct berval *berval = NULL;
	int found = 0;
	int i;

	if ( (ber = der_alloc ()) == NULL )
	{
		goto bailout;
	}

	/* begin sequence, enumeration, end sequence */
	ber_printf ( ber, "{e}", rc );
	if ( ber_flatten ( ber, &berval ) != LDAP_SUCCESS )
	{
		goto bailout;
	}
	gerrespctrl.ldctl_oid = LDAP_CONTROL_GET_EFFECTIVE_RIGHTS;
	gerrespctrl.ldctl_iscritical = iscritical;
	gerrespctrl.ldctl_value.bv_val = berval->bv_val;
	gerrespctrl.ldctl_value.bv_len = berval->bv_len;

	slapi_pblock_get ( pb, SLAPI_RESCONTROLS, &resultctrls );
	for (i = 0; resultctrls && resultctrls[i]; i++)
	{
		if (strcmp(resultctrls[i]->ldctl_oid, LDAP_CONTROL_GET_EFFECTIVE_RIGHTS) == 0)
		{
			/*
			 * We get here if search returns more than one entry
			 * and this is not the first entry.
			 */
			ldap_control_free ( resultctrls[i] );
			resultctrls[i] = slapi_dup_control (&gerrespctrl);
			found = 1;
			break;
		}
	}

	if ( !found )
	{
		/* slapi_pblock_set() will dup the control */
		slapi_pblock_set ( pb, SLAPI_ADD_RESCONTROL, &gerrespctrl );
	}

bailout:
	ber_free ( ber, 1 );	/* ber_free() checks for NULL param */
	ber_bvfree ( berval );	/* ber_bvfree() checks for NULL param */
}

int
acl_get_effective_rights (
	Slapi_PBlock    *pb,
	Slapi_Entry	    *e,			/* target entry */
	char			**attrs,	/* Attribute of	the entry */
	struct berval   *val,		/* value of attr. NOT USED */
	int		    	access,		/* requested access rights */
	char			**errbuf
	)
{
	Slapi_PBlock *gerpb = NULL;
	void *aclcb = NULL;
	char *subjectndn = NULL;
	char *gerstr = NULL;
	int gerstrsize = 1024;
	unsigned long entryrights;
	int iscritical = 1;
	int rc;

	*errbuf = '\0';
	gerstr = slapi_ch_malloc ( gerstrsize );

	/*
	 * Get the subject
	 */
	rc = _ger_parse_control (pb, &subjectndn, &iscritical, errbuf );
	if ( rc != LDAP_SUCCESS )
	{
		goto bailout;
	}

	/*
	 * The requestor should have g permission on the entry
	 * to get the effective rights.
	 */
	rc = _ger_g_permission_granted (pb, e, errbuf);
	if ( rc != LDAP_SUCCESS )
	{
		goto bailout;
	}

	/*
	 * Construct a new pb
	 */
	rc = _ger_new_gerpb ( pb, e, subjectndn, &gerpb, &aclcb, errbuf );
	if ( rc != LDAP_SUCCESS )
	{
		goto bailout;
	}

	/* Get entry level effective rights */
	entryrights = _ger_get_entry_rights ( gerpb, e, subjectndn, gerstr, errbuf );

	/*
	 * Attribute level effective rights may not be NULL
	 * even if entry level's is.
	 */
	_ger_get_attrs_rights ( gerpb, e, subjectndn, attrs, &gerstr, &gerstrsize, errbuf );

bailout:
	/*
	 * Now construct the response control
	 */
	_ger_set_response_control ( pb, iscritical, rc );

	if ( rc != LDAP_SUCCESS )
	{
		sprintf ( gerstr, "entryLevelRights: %d\nattributeLevelRights: *:%d", rc, rc );
	}

	slapi_log_error (SLAPI_LOG_ACLSUMMARY, plugin_name,
		"###### Effective Rights on Entry (%s) for Subject (%s) ######\n",
		slapi_entry_get_ndn (e), subjectndn);
	slapi_log_error (SLAPI_LOG_ACLSUMMARY, plugin_name, "%s\n", gerstr);

	/* Restore pb */
	_ger_release_gerpb ( &gerpb, &aclcb, pb );

	/*
	 * General plugin uses SLAPI_RESULT_TEXT for error text. Here
	 * SLAPI_PB_RESULT_TEXT is exclusively shared with add, dse and schema.
	 * slapi_pblock_set() will free any previous data, and
	 * pblock_done() will free SLAPI_PB_RESULT_TEXT.
	 */
	slapi_pblock_set (pb, SLAPI_PB_RESULT_TEXT, gerstr);

	if ( !iscritical )
	{
		/*
		 * If return code is not LDAP_SUCCESS, the server would
		 * abort sending the data of the entry to the client.
		 */
		rc = LDAP_SUCCESS;
	}

	slapi_ch_free ( (void **) &subjectndn );
	slapi_ch_free ( (void **) &gerstr );
	return rc;
}